Apparatus for coating metal strip or wire



{M 4,1943. 5. 11451? EI'AL 2,318,419

'APBARATUs' FOR comma METAL STRIP 0R WIRE Filed 001. 31, 1940Sheets-Sheet 2 4 INVENTORS [rnexffi P/off A ano'domiffambr' Patented May4, 1943 UNITED STAT as PAT au'r orrics Arman-us FOR ooa'rmq Maui.- s'rmw on. wmn

- Ernest a. llott ee John a. Stanier, resume", ungstown 8 Ohio,aseignors to The Yo Tube Company, Youngstown, Ohio, a eorpora-- tion ofOhio Application o tebes- 31, 1940, Serial No. 363,650

. 1 Claim. (01. 91-125) This invention relates to the coating of metalin the form of 'strip' or wire. It will be described herein as appliedspecifically to the application of a protective coating such as zinc toferrous strip although the principles ofthe invention may be applied aswell to the coating of other materials such as wire.

In the coating of sheet metal or wire as heretofore carried out, thebase metal has been pickled inan acid solution prior to passing througha bath of molten zinc. The pickling operation is quite costly because ofthe expense "of providing and maintaining the necessary equipment. Inaddition, it requires a considerable amount of time, and workingconditions in the vicinity of the pickling equipment are quite severeunless expensive precautions are taken.

We have invented a novel apparatus for coat- ;ing sheet metal andparticularly ferrous strip or wire, whereby the aforementionedobjections are overcome. In a preferred embodiment and practice of theinventioruwe provide means for mechanically descaling the stripprogressively prior to the actual coating. 4 We then pass the stripprogressively through a coating bath and suspend it on emergingtherefrom, free from contact with any support for a period sufllcienttocause solidification of the coating. The strip is then sheared intolengths or coiled.

The accompanying drawings illustrate dia grammatically the embodimentand practice outlined above and a modification thereof. In the drawings,

Fig. 1 is a central, longitudinal, sectional view through several piecesof apparatus which operate successively on the strip: and

Figs. 2 and 3 togetherconstitute a similar view Referring now in detailto the drawings, the apparatus of our invention includes an uncoller m uInn rolls I.

of a modification.

ads. to hold a coil of strip 11 while the portion of the coil passingthrough the processing apparatus being designated S.

Adjacent the uncoiler is a device I: for 10mingsuccessivevcoiis end toend. This device may be a butt-welder or a stitcher, both of which arewell and require no detailed description. The device I! preferablyincludes a guide roll it and driverpinch rolls ll on opposite sidesthere and ii causes the layers of scale adhering to the descalingapparatus it. a guide roll I I, driven entering and exit pinch rolls i8and i9, bendingrolls 20 and 2!, and

abrasion .devices 22, preferably rotary wire brushes. The descalingapparatus is enclosed in a housing iia. As shown in the drawings, the

strip is pulled from the coil Ii by the-pinch rolls I4 and is fedthrough the descaling apparatus It.

After passing over the guide roll I! and through the pinch rolls l8thereof, it is bent in opposite directions around the bending rolls 20and 21 prior to passing through the pinch rolls i0 and out of thedescaling apparatus. The pinch rolls i8 and i9 maintain the strip tautand thereby insure that it is sharply bent progressively in oppositedirections, beyond the elastic limit.

The. bending of the-strip around the rolls 20 surfaces thereof to befragmented and at least partly detached. The bending also loosens thebond between the scale and the base metal to an extent that anyfragmented particles not immediately detached may readily be removed byabrasion. This is effected by the rotary wire brush which engageopposite surfaces of'the strip at points where'they are convexly bent.-

After the strip has passed through the apparatus ii, it is entirelyscale-free and ready for The coating apparatus 23 is located closelyadiacent the descaling apparatus Ii and preferably comprises a pct 24 orother suitable container for a bath of coating material such as moltenzinc, the surface of which is indicated at 2!. Entry rolls 26,'bottomrolls .21 and exit rolls 2. are Journaled in suitable bearings (notshown) 7 in the pot and guides 29 and 30 between the c v by coil-supp rbeing unwound and processed in single thickness,

several sets of rolls tend to confine the strip to apredetermined paththrough the pot. These rolls are, driven by suitable mechanism to feedthe strip progressively through the pot'. The de scaled strip traversingthe pot 24 is coated uniformly onbothsides with a thin layer of zinc,inthe known manner.

The strip emerging from the pct 24 passes upwardly flzherefromthroughout a considerable distance as indicated at 3|, free, fromcontact with any support. Eventually,\the strip passesortogethcrwitnstripartslh'whlen maybeelectrodesifthedeviceisaweldenordles'ifthedeviceisastitcher.

the strip-Joining I2 is a over a guide roll 32 so positioned relative tothe pot II as to provl e a cooling zone .therebetween of. such length bythe time the strip'reaches the roll :2, the coating has been cooled andsolidified with the accompaniment of the formation oftheusual by contactwith the, roll This apparatus includes es. This preventsthe' coat- 32.The roll 32 may be idle or driven, but is preferably driven to reducethe possibility of slippage of the strip thereon.

From the supporting roll 32, the strip passes downwardly to a pinch-rollunit 33 including driven pinch rolls 34 and a guide roll 35. The pinchrolls 34 maintain the portion of the strip between them and the exitrolls 28 of. the galvanizing pot substantially taut and deliver thestrip to a recoiler 36 of known construction.

Between the pinch-roll unit 33 and the recoiler 36, a shear 31, also ofknown construction, is disposed. The shear has supporting rolls 38 onopposite sides thereof and is operated to cut out the joints betweensuccessive strip lengths, formed by the device [2. Alternatively, thestrip may be sheared to length by continued operation of the shear 31.It will be understood that if the strip is to be recoiled after coating,the shear remains stationary with its blades in open position so thatthe strip may pass freely therebetween.

While the passage of the strip through the several pieces of processingapparatus will in general be continuous, temporary stoppages thereof areobviously necessary to permit joining of successive lengths by thedevice l2 and the cutting out of the joints by the shear 31. To permitsuch stoppages without interfering with continuous progress of the stripthrough the descaler and galvanizing pot, loops of surplus material 39and 40 may be gathered between the device i2 and the descaling apparatusI6 and between the pinch-roll unit 33 and the shear 31.

Referring now to Figs. 2 and 3 showing a modifled apparatus, an uncoiler40 is adapted to support a coil 4! as it is being unwound. The strip isunwound from the coil by pinch rolls 42 and is passed through a rollerleveler 4.3. After passing through the leveler, the strip enters abending and brushing unit 44. Pinch rolls 45 feed the strip betweenguides 45 and around bending rolls 41 and 48.- These rolls are magneticand we provide means for magnetizing them successively in order to feedthe leading end of the coiled strip therebetween.

When the leading end of the coil approaches the roll 41, it ismagnetized, thereby attracting the strip end and carrying it around theroll. When the leading end of the strip approaches the median planebetween the rolls 41 and 48, the roll 41 is de-magnetizedand the roll 48is magnetized. The leading end of the strip is thus passed from the roll41 to the roll 48.

Guides 49 lead the strip from the roll 48 between exit pinch rolls 50,the roll 43 being demagnetized when the leading end of the stripapproaches the guides 43.

Rotary wire brushes adjacent the rolls 41 and 48 perform the samefunction on the strip as the rolls 22 of Fig. 1, i. e.,subject it toavigorous brushing while it is convexly bent, thereby removing the scalefrom both surfaces of the strip.

The strip enters a. roller leveler 52 after leaving the bending andbrushing unit 44. The leveler 52 includes pinch rolls 53 and levelingrollscessively carried away by a belt conveyor 53.

.The conveyor 56 delivers the sheets to a galvanizing pct 51. The pot issupported in a setting 58. Pinch rolls 59 deliver sheets from theconveyor 58 through guides 58 to entry rolls 61 of the galvanizing pot.Bottom rolls 62 and exit rolls 83 convey the sheets through the spelter'bath in the pot 51, the path of the sheets being determined by guides 64and 65.

Sheets discharged from the exit rolls 53 of the galvanizing pot arediverted on to a spangleforming conveyor 66 by a deflector guide 51. Thecoated sheets are cooled as they travel along the conveyor 61 and thecustomary spangles have fully formed by the time they reach thedischarge end thereof. The'partly cooled and coated sheets are thenpassed through a roller levele: B8 and delivered immediately on to aroll table 59 from which they are picked up successively by a coolingrack or wheel 10.. This device is of wellknown construction and compriselateral arms 1i arranged in rows on a rotating shaft 12 at one side ofthe roll table 69. The cooling wheel travels at a relatively low speedand the sheets are cooled by contact with the air as the wheel turns.The sheets are finally removed from the wheel by hand.

It will be apparent from the foregoing description that the invention ischaracterized by numerous advantages over the apparatus used heretoforein coating sheet metal. In the first place, the cost of the descalingoperation carried out according to our invention is much'less than thatof the ordinary acid pickling. The apparatus is much less costly andmore compact and maybe operated at higher strip speeds (i. e., 300 feetper minute) than have been obtainable in the conventional picklinglines. A further advantage of great importance is that the coatingproduced by our apparatus exhibits greater adv herence to the base metalthan the coating applied to material subjected to the conventional acidpickling. Because of its small size, the descaling apparatus may befully enclosed as indicated in the drawings so that working conditionsin the neighborhood are not objectionable. The operating personnelrequired by the apparatus is much smaller than that required by theusual pickling line.

Although we have illustrated and described but a preferred embodimentand practice of the spaced rolls and means for bending thestripprogressively around said rolls in opposite-directions, said rollsbeing small enough to cause fragmentation and at least partialdetachment of the. scale adhering to the strip, rotary wire brushesengaging the strip at points where it is convexly bent around said rollsand a coating bath adapted to be traversed progressivelyby the strip. 7

ERNEST 3. PLUM. JOHN S. STANIER.

